fix: route Safari < 16.5 users to legacy path

For Safari < 16.4 where VAPID isn't available, returns  early so users are routed through the legacy Safari push path. This is the only path that works on those browsers. On Safari 16.4+ the existing logic still applies: only users with an active legacy subscription (granted + deviceToken) use the legacy path.

Author: sherwinski

src/shared/environment/detect.ts

@@ -20,14 +20,16 @@ export const supportsServiceWorkers = () => {
 export const windowEnvString = IS_SERVICE_WORKER ? 'Service Worker' : 'Browser';
 
 /**
- * Returns true only when the user has an active legacy Safari push subscription.
+ * Returns true when the legacy Safari push path should be used.
  *
  * Safari 16.4+ supports standard Web Push (VAPID), but `window.safari.pushNotification`
  * was never removed. Previously this function returned true whenever that API existed,
  * which forced ALL macOS Safari users onto the legacy path — even on browsers that
  * fully support VAPID. Now we check the actual permission state: only users who have
  * already granted legacy push (and have a deviceToken) stay on the legacy path, because
  * Safari doesn't support migrating from legacy push to standard web push.
+ *
+ * On Safari < 16.4, VAPID is not available so the legacy path is the only option.
  */
 export const useSafariLegacyPush = (): boolean => {
   if (!isBrowser() || window.safari?.pushNotification == undefined) {
@@ -36,6 +38,12 @@ export const useSafariLegacyPush = (): boolean => {
   const safariWebId = OneSignal?.config?.safariWebId;
   if (!safariWebId) return false;
 
+  const hasVapidSupport =
+    typeof PushSubscriptionOptions !== 'undefined' &&
+    // eslint-disable-next-line no-prototype-builtins
+    PushSubscriptionOptions.prototype.hasOwnProperty('applicationServerKey');
+  if (!hasVapidSupport) return true;
+
   const { permission, deviceToken } =
     window.safari.pushNotification.permission(safariWebId);
   return permission === 'granted' && deviceToken != null;